Process for textile treatment



May 5, 1970 J w. CASE ETAL 3,510,250

PROCESS FOR TEXTILE TREATMENT Filed April 10, 1967 2 Sheets-Sheet l 1 FIG- 2 A .ZZ/KFA F j jy v MQl/A'M (Z65 JZ Y F 3 Mid 4% May 5, 1970 w, CASE ET AL 3,510,250

PROCESS FOR TEXTILE TREATMENT Filed April 10, 1967 2 Sheets-Sheet 2 MQgZgMM United States Patent US. Cl. 8139.1 6 Claims ABSTRACT OF THE DISCLOSURE Woven textiles are treated in continuous lengths and open widths by immersion in boiling dry-cleaning solvents by passing the fabric through the boiling solvents and the zone of ebullition in the solvents so that the edges of the fabric are not contacted by the zone of ebullition and hence the tendency of the fabric emerging from the process to be creased is significantly mitigated.

This invention relates to the treatment of textiles with boiling liquids, and particularly to the treatment of woven textile fabrics with boiling organic solvents, commonly termed solvent scouring.

It is known to treat textile materials with organic sol vents to dissolve away grease and other contaminants from them, and this treatment is often carried out using a boiling solvent in order to make the process as rapid as possible. For treating fabrics in open width, it is common to run the fabric through a bath of boiling solvent and to guide the cloth by means of rollers, some of which are submerged in the solvent bath. One disadvantage often encountered with such processes is the tendency for the fabric emerging from the process to be creased, so that further treatment is necessary to obtain a smooth finish.

We have found that the creasing can be greatly reduced by keeping the source of ebullition in the solvent away from the edges of the fabric as it passes over the submerged rollers, so as to avoid a flow of vapour bubbles inwards from the edge towards the centre of the fabric Width and especially to avoid an overall lateral flow of vapour bubbles across the fabric width from one side to the other.

Thus according to our invention we provide an improved process for treating woven textile fabrics in continuous length and in open width by immersion in a boiling liquid wherein the fabric is passed through a bath of boiling liquid and the zone of ebullition in the liquid is located so that it does not include the zone where the edge of the fabric passes around fabric guides immersed in the liquid.

According to our invention we also provide an apparatus for treating woven textile fabrics in continuous length and in open width by immersion in a boiling liquid which comprises a tank to contain the liquid, guides for transfer of fabric through the tank and a heating element positioned in the tank so that the zone of ebullition of a liquid when contained in the tank does not include the zone where the edge of the fabric passes around the guide.

The heater element is preferably positioned so as to be immersed in a bath of liquid contained in the tank and so that the stream of bubbles formed by the boiling of the liquid in contact with said heating element and rising through the body of liquid impinges upon the fabric as it passes over the guides or rollers and is distributed evenly in an outward direction over the width of the fabric i.e. from the central region towards each Patented May 5, 1970 edge of the fabric width. This distribution of the stream of bubbles helps to open out the fabric rather than move it in from the edges. The action of the vapour bubbles moving out equally to each edge of the fabric can in some circumstances be said to simulate the action of a scroll roller or an expander roll.

The heater element or elements may be any conventional type of element, for example one operating by electric or steam heating, and may be for example of strip, loop or coil form and may be used singly or in groups. The heater element may be fitted at the bottom of the tank in a central position relative to the rollers or guides over which the fabric passes, as this arrangement makes it easier for the whole of the heating surface to be in the desired position. Alternatively there may be used a conventional type of heater which is fitted at the side of the tank so as to project into the tank and lie underneath the rollers or guides. When this side-fitting form is used, it should be positioned so as to lie entirely in the desired position relative to the fabric transport rollers (i.e. in a direction transverse to the axes of the rollers or guides) or it should be provided with a protecting shield or cover to reduce heat transfer from it to the liquid in the zone beneath the edge or edges of the fabric. Such a shield may be an insulating or spaced sleeve fitting around the heater element. As an alternative to providing such shields, deflector plates fitted around the heating element to deflect the boiling liquid away from the edges of the fabric and rollers can be used, though their beneficial effect is in general not so marked.

The proportions of the fabric which should be kept from exposure to the bubbles in the boiling solvent may vary to some extent with the particular fabric and liquid used, and of course with the standard of finish required. Too narrow a heating zone may, of course, make it more difficult to introduce sufiicient heat to keep the bath boiling actively, so the best working range of size for the ebullition zone is about 70% to of the fabric width, preferably placed approximately centrally With respect to the fabric. In general, we prefer to keep at least the outermost 10% on each side of the fabric clear of the ebullition zone, e.g. the outermost 6 inches at each side of a 60 inch width of fabric.

To secure such a clearance, allowance needs to be made in positioning the heater element in the tank for the spreading pattern of bubbles rising from the heater element, but for most known applications the spread is such that the dimensions of the heater may be taken as being substantially those of the ebullition source.

Apart from this feature of restricting the size and position of the ebullition source and hence of the ebullition zone, the basic method of treating the fabric in boiling liquids (e.g. solvent scouring) is unchanged, and the temperatures, treatment times, solvents, additives and other integers of the process need no appreciable change.

The invention is especially useful and advantageous when a light weight textile fabric is being treated, and also when the treating liquid is one having low viscosity and surface tension. Our invention is also advantageous when using a textile fabric having relatively slippery surfaces (e.g. one made up of synthetic fibres, or mixtures of these with other components); examples of such fabrics include those made in Whole or in part from polyamide (nylon) or polyester fibres. Suitable solvents for use in the process and apparatus of our invention include trichloroethylene, perchloroethylene, trichlorotrifluoroethane (particularly 1:1:2-trichloro-1:2z2-trifiuoroethane) and mixtures thereof, but the same principles can apply for other boiling liquid systems, for example aqueous systems.

The invention may if desired be used in the fixation on, or removal of, dyestuffs from fabrics for example as is more fully described in Belgian Patent No. 687,651 and UK. application No. 1,986/67.

The invention is illustrated but not limited with reference to the accompanying drawings wherein FIGS. 1 and 2 are vertical sections, taken transversely and longitudinally respectively, of an apparatus for carrying out the process, and FIG. 3 is a horizontal section of a steam heating coil for use in the apparatus represented in FIGS. 1 and 2.

In FIGS. 1 and 2, a tank 1 is fitted with rollers 2 over which a continuous length of fabric in open width 3 is passed. The body of the tank 4 is filled with solvent up to the level 5 (commonly termed the liquor level). At the bottom of tank 1 is a flanged port 6 provided with a cover panel or door 7 through which a steam coil 8 is connected, and provided with steam inlet and outlet pipes 9. The steam coil 8 is fitted with shrouds to limit heat transfer. The apparatus may be provided with conventional condensing apparatus for solvent vapours (not shown) and may be in the form of a compartment for inclusion as part of a larger or multi-stage plant.

In FIG. 3, the steam coil 1 is made as a U-shaped piece of metal tubing which passes through the panel 2 at two points and the joints 3 and 4 are sealed by welding. Around the steam coil 1 adjacent to the panel 2, are fitted shrouds 5 made of tubular metal sealed by welded joints 6 and 7 to the panel 2 and the heating element 1 respectively. Vents 8 are provided through the panel 2 to connect the interior space between coil 1 and shroud 5 with the outside atmosphere to allow air circulation. Threaded connections 9 and 10' are provided for connecting steam inlet and outlet pipes to the heating coil. In use, the panel 2 is fitted to a suitable opening in a tank, and the coil 1 protrudes into the body of the tank.

The invention is also illustrated but not limited by the following examples.

Example 1 A length of a synthetic fibre blend (polyester/rayon) fabric of 60 inch width was run through a bath of boiling trichloroethylene in an apparatus as represented in the accompanying drawings, in which there were fitted 36 rollers (30 of these being immersed and 6 not immersed in the trichloroethylene) each of 72 inches width and in which a steam heating coil is positioned 6 inches below the immersed rollers and shrouded so as to limit the heating surface of the coil to a length extending for a distance of 42 inches, centrally disposed under the rollers. The fabric was passed through the bath at 180 feet per minute and then into a steam tower at 90 C.100 C. to volatilize the solvent from it. The resulting fabric was found to be substantially free from creases.

Example 2 The procedure of Example 1 was repeated using a polyester/polynosic fabric, and similar results were obtained.

Example 3 The procedure of Example 1 was repeated using a polyester/coton fabric and similar results were obtained.

Example 4 The procedure of Example 1 was repeated using a polyester/ worsted fabric and similar results were obtained.

What We claim is:

1. Process for treating woven textile fabrics in continuous length and in open width by immersion in a boiling liquid which is drycleaning solvents wherein the fabric is passed through a bath of boiling liquid and the zone of ebullition in the liquid is located so that it does not include the zone where the edge of the fabric passes around fabric guides immersed in the liquid.

2. Process as claimed in claim 1 wherein the zone of ebullition is about to of the fabric width placed approximately centrally with respect to the fabric.

3. Process as claimed in claim 1 wherein the outermost 10% on each side of the fabric is clear of the zone of ebullition.

4. Process as claimed in claim 1 wherein the textile fabric to be treated is selected from the group consisting of wholly synthetic fibers and partly synthetic fibers.

5. Process as claimed in claim 4 wherein the synthetic fiber is selected from the group consisting of polyester fiber and a polyamide fiber.

6. Process as claimed in claim 1 wherein the treating liquid is selected from the group consisting of trichloroethylene, perchloroethylene, trichlorotrifiuoroethane and mixtures thereof.

References Cited UNITED STATES PATENTS 3,384,445 5/1968 Gilbert 8l39.1XR

MAY'ER WEINBLATT, Primary Examiner US. Cl. X.R. 

